1. Field of the Invention
The invention is directed to an athermal design which maintains the characteristics of the wavelength division multplexed filters (center wavelength, bandwidth, etc.) as invariant as possible with respect to temperature fluctuations.
2. Description of the Prior Art
Holographic filters can be employed for wavelength division multplexed applications. Temperature dependence is a critical concern for telecommunication. In thin film filter technology, by a wise choice of materials, thermal drift can be compensated for by deposing alternate layers of materials with opposite thermal expansion coefficients to fabricate athermal thin film filters. However, such flexibility isn't available in bulk holographic filters. A feasible system solution will be proposed to compensate for the effects of temperature changes.